Slip ring assembly

ABSTRACT

A CARRIAGE HAVING A PAIR OF DRIVEN WHEELS, EACH WHEEL OF THE PAIR BEING DRIVEN BY A SEPARATE ELECTRIC MOTOR TO PERMIT DIFFERENTIAL STEERING OF THE CARRIAGE. A SLIP RING ASSEMBLY IS PROVIDED ON THE CRRIAGE AND FORMS A PART OF A FEED PATH FOR SUPPLYING POWER TO THE ELECTRIC MOTORS. THE CARRIAGE CAN BE ARRANGED IMMEDIATELY BELOW A BOARD ON WHICH A TOY VEHICLE STANDS AND CAN BE INDIRECTLY COUPLED TO THE TOY VEHICLE BY A PERMANENT MAGNET.

Dec. 12, 1972 AHMED 3,705,996

SLIP RING ASSEMBLY Original Filed Aug. 25, 1969 3 Sheets-Sheet 1 INVENTOR Kumul Ahmed Dec. 12, 1972 K. AHMED 3,705,996

SLIP RING ASSEMBLY Original Filed Aug. 25, 1969 3 Sheets-Sheet 2 52 55a 56 5/ A; 5 5a 55 INVENTOR Komol Ahmed Dec. 12, K. AHMED SLIP RING ASSEMBLY 3 Sheets-Sheet 5 Original Filed Aug. 25, 1969 INVEA/TUR Kumol Ahmed United States Patent 3,705,996 SLIP RING ASSEMBLY Kamal Ahmed, Stanmore, England, assignor to AMP Incorporated, Harrisburg, Pa.

Original application Aug. 25, 1969, Ser. No. 852,702, now Patent No. 3,574,266. Divided and this application Jan. '8, 1971, Ser. No. 104,943

Int. Cl. H01r 39/08 US. Cl. 310-232 3 Claims ABSTRACT OF THE DISCLOSURE This is a division of application Ser. No. 852,702, filed Aug. 25, 1969, now Pat. No. 3,574,266.

This invention relates to a carriage for driving and steering toy vehicles and in particular, to a slip ring assembly by which an electric current can be supplied to electric motors forming part of such a carriage.

According to one aspect of the present invention, a wheeled carriage for driving and steering toy vehicles comprises a pair of wheels, each wheel being drivable by an individual electric motor, a slip ring assembly forming part of a feed path for an electric current to each electric motor, the slip ring assembly including a plurality of slip rings mounted on the carriage and a plurality of corresponding spring contacts mounted for relative rotational movement with respect to the carriage and adapted for connection to an electrical power supply, each spring contact slidably engaging one slip ring for maintaining electrical contact with the slip ring during relative rotational movement of the spring contacts and the carriage, and means for coupling the carriage to a toy vehicle such that when the carriage is being operatively driven and steered, in response to the power supplied to the electric motors, movement of the carriage will cause corresponding movement of the toy vehicle.

According to a further aspect of the present invention, a slip ring assembly comprises a plurality of annular slip rings spaced by annular electrically insulating washers coaxially arranged with the slip rings, each slip ring having a radially inwardly extending projection for connection to a conductor wire.

According to a still further aspect of the invention, a slip ring of generally annular configuration comprises a projection extending radially inwardly towards the center of the annulus, the projection being adapted for connection to a conductor wire.

Preferably, the spring contacts are each crimped to an end of a conductor of a flat tape cable which is, at its opposite end adapted to be connected to a device, for example, a potentiometer for varying the voltage applied to each electric motor thereby enabling the carriage to be dilferentially steered. The tape cable can further be connected to a switch for reversing the polarity of the electric motors to permit the carriage to be driven in a reverse as well as a forward sense. The tape cable can also be connected to a device such as a rheostat for controlling the supply of current to the electric motors to effect alteration of the speed of the carriage.

One advantage of using fiat tape cable is that since tape cable can be produced having a very small thickness, in

the order of 0.010 to 0.015 inch, should the carriage be steered over the cable, the step over which it must roll is very small.

In one embodiment the slip rings are of generally annular configuration and have a skirt with which the corresponding spring contact engages. The spring contact has a generally elongate body which has at one end a ferrule part'for crimping to a conductor of a flat tape cable and at the opposite end a contact part formed out of the plane of the body for engaging the skirt of a slip ring.

.In a modification, the slip rings are of generally annular configuration and have a groove formed in one side which gives a. corresponding annular rib on the opposite side. The corresponding spring contacts each have a generally elongate body which is forked at one end, the prongs of the fork each engaging with a surface of the annulars and having means on one prong for engaging within the groove in the annulus.

The coupling means may be a permanent magnet which attracts a permanent magnet attached to the toy vehicle.

An embodiment of the invention will now be described by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 is a diagrammatic cross-sectional view through a wheeled carriage according to the invention;

FIG. 2 is a diagrammatic cross-sectional view on the lines 11-11 of FIG. 1;

FIG. 3 is a top plan view of a slip ring;

FIG. 4 is a side elevational view of the slip ring of FIG. 3;

FIG. 5 is a top plan view of a spring contact before crimping to a conductor of a tape cable;

FIG. 6 is a side elevational view of the spring contact of FIG. 5;

FIG. 7 is a diagrammatic view showing the wheeled carriage of FIG. 1 ararnged to drive a toy vehicle;

FIG. 8 is a side elevational view of a modified slip ring and a modified spring contact; and

FIG. 9 is a top plan view of the slip contact of FIG. 8.

As shown in FIGS. 1 and 2, a carriage 1, for driving and steering a toy vehicle, for example, a toy car 2, (see FIG. 7), comprises a generally rectangular hollow base member 3 suported on four wheels 4. Each wheel 4 of the front pair of wheels is driven through gearing 5 and 6 by an electric motor 7 mounted on the base member 3.

A support member 10 of electrically insulating material is provided on the upper surface 8 of the base member 3. The support member 10 has a central through hole 14, a longitudinal slot 24 and a circumferential groove '11 extending around its outer surface. Fixedly mounted around the support member 10 are three electrically conductive slip rings 15, separated by electrically insulating washers 16, which form part of a slip ring assembly.

As shown in FIGS. 3 and 4, each slip ring 15 consists of an annulus 15a having a skirt 17 depending from its outer edge. The inside edge of the annulus has a projection 18 extending towards the center of the annulus. Each projection 18 extends into the slot 24 and has along its edges two upstanding arms 19 each having a serrated edge for crimping to a conductor wire 41, 42, 43. Each conductor wire 41, 42, 43 extends from a projection 18 through hole 14 to one or the other of the electric motors 7 or to a commoning point between the motors.

A magnet 25 is attached to the end of the support member 10 remote from the base member 3, which magnet 25 extends partially through a hole 26 in a cover 21. The cover 21 has two struts 20 which engage at their inner ends in the groove 11. The ends of the struts 20 within the groove 11 are so arranged that the struts 20 ring and the spring together with the cover 21 can rotate freely around the support member 10.

Secured to the inside surface of the cover 21 is a housing 22 into which three contact springs 30 are releasably secured.

As shown in FIGS. and 6, each spring contact 30 has an elongate body 31 having at one end a ferrule part 32 comprising two upstanding arms 33 and two formedout tines 34 and at its opposite end a contact part 35 formed out of the plane of the body 31. Between the ferrule part 32 and the contact part 35 is a protrusion 36 which secures the spring contact within the housing 22. Each spring contact 30 is crimped by means of ferrule part 32 to a conductor 39 of a flat tape cable 40 and its contact part 35 is arranged to slidably contact the corresponding skirt 17 of one of the slip rings 15."

The tape cable 40 leads to a potentiometer (not shown) simulating a steering wheel such that rotation of the steering wheel relatively increases or decreases the voltage applies to one or other of the two electrical motors 7 to cause one of the pair of driven wheels 4 to rotate faster than the other wheel 4. By differentially driving the wheels 4 a steering effect is obtained on the carriage 1. The tape cable 40 can also be connected to a switch -(not shown) for reversing the polarity of the electric motors 7 to allow the carriage 1 to be reversed. The tape cable can also be connected to a rheostat or similar device (not shown) which is arranged to simulate an accelerator pedal for increasing or decreasing the current to the electric motors to increase or decrease the speed of the carriage 1.

As shown in FIG. 7, the carriage 1 is placed on the upper surface of a flat board 50 so that the magnet 25 is arranged at a predetermined distance from a further board 52 arranged parallel with the board 50. A toy car 2, is placed on the upper surface of board 52, which board can have roads or the like painted on its surface or toy buildings arranged on its surface. The toy car 2 has a magnet 54 attached to its body. The polarities of the magnets 25 and 54 are arranged such that attraction takes place between the magnets. Movement of the car riage 1 will, therefore, cause the toy vehicle 2 to move across the upper surface of the board 52. The carriage 1 may be enclosed so that a person controlling the toy car 2 by means of the potentiometer, switch and rheostat will only see the toy car 2 and will not see the carriage 1.

One advantage of the above described embodiment is that the arrangement of the spring contacts each wiping around the skirt 17 of a slip ring 15 offers very little frictional resistance to the rotational movement of the cover 21 with respect to the support member 10. This has the effect that the response of the carriage to the steering and driving controls is fast which allows for accurate maneuvering of the carriage.

FIGS. 8 and 9 illustrate a modified slip ring assembled to a modified spring contact.

The slip ring 100 is of generally annular configuration and is of sheet brass or some suitable conductive material having an annular groove 103 formed on one surface which gives a corresponding annular rib 104 on the opposite surface. The inside edge of the annulus has a projection 118 extending towards the center of the annulus. The projection 118 has, along its edges, two upstanding arms 119, each having a serrated edge for crimping to a conductor wire. Opposite the projection 118, there is located a polarizing projection 106 which ensures that the annulus can be mounted and maintained in a predetermined position.

The spring contact 102 is formed as a simple stamping from phosphor bronze or some similar material, is

' generally elongate, and has two prongs 107, 108, at one end which overlie each other. The upper prong 107, as seen in FIGS. 8 and 9, is provided with a dimple 110 which engages in the groove 103 in the slip ring 100. The other prong 108 is provided with a dimple 111 which lies alongside the radially inner surface of the rib 104 when the contact 102 is assembled with the slip ring 100.

The spring contact 102 is further provided with a crimping ferrule 112 at the opposite end from the prongs 107, 108. The prongs 107, 108 are resiliently biased towards each other and, therefore, grip the slip ring between them. The resilience is derived from .the material and is such as to enable a good electrical contact to be made between the slip ring 100 and the spring contact 102 while allowing relative sliding movement between them. The spring contact 102 is able to slide around the slip ring 100 with the dimple 110 in constant engagement with the groove 103. The effect of the dimple 110 in the groove 103 and the .dimple 111 against the rib 104 is such as to retain the slip-ring 100 and the spring contact 102 together when relative rotary movement occurs.

The invention is claimed in accordance with the fol lowing:

1. A slip ring assembly comprising a hollow dielectric carrier member having a slot extending from an outside surface to an inside surface of said carrier member, a slip ring defining an annulus disposed on said carrier member and having an annular contact-engaging surface, a projection extending outwardly from an inner periphery of said annulus and extending inwardly toward a center of said slip ring, said projection being disposed in said slot, means on said projection for connection with a conductive means, a spring contact member, dielectric carrying means carrying said spring contact member, a contact section of said spring contact member electrically engaging said contact-engaging surface, and conductorconnecting means of said spring contact member for connection with other conductive means.

2. A slip ring assembly according to claim 1 wherein said annular contact-engaging surface comprises an annular skirt depending from an outer periphery of said annulus and extending along a section of said outer surface of said carrier member.

3. A slip ring assembly according to claim 1 wherein said annular contact-engaging surfaces comprises top and bottom surfaces of said annulus, an annular groove n said top surface and a corresponding annular rib in said bottom surface, said contact section having aligned prongs, one of said prongs having a dimple in engagement with said annular groove, the other of said prongs having a dimple disposed alongside a radial inner surface of said annular rib.

References Cited 4/1902 France 339-5 GERALD M. FORLENZA, Primary Examiner D. W. KEEN, Assistant Examiner US. Cl. X.R. 191l2 R 

